Affiliations: University of Maryland School of Medicine, Baltimore,
MD, USA | North Shore Long Island Jewish Health System,
Farmingdale, NY, USA | Health Economics Research Group, University of Miami,
Coral Gables, FL, USA
Note: [] Corresponding author: Rita Prasad Verma, M.D., University of
Maryland School of Medicine, Department of Pediatrics, Division of Neonatology,
29 S. Greene Street, GS 110K, Baltimore, MD 21201, USA. Tel.: +1 410 328 6003;
E-mail: rverma@peds.umaryland.edu
Abstract: Background: Early postnatal weight changes are widely variable and
unpredictable in the extremely low birth weight infants (ELBW, birth weight
< 1000 g). As the fluid volume therapy is calculated based on the body
weight these changes could potentially have implications in the hydration
related morbidities in them. Early postnatal weight changes have not been
systematically investigated in this population. Objectives: To determine
the pattern and magnitude of weight changes early in life and its relationship
with maturation and birth weight (BW) in ELBW infants. Methods: We
studied the maximum weight loss (MWL), and the daily body weight changes from
birth weight (DΔ bw) during the first 15 days of life.
Prospectively entered infants' and maternal demographic and relevant clinical
data were retrospectively extracted via computerized reports and chart reviews
during a three-year study period. MWL and DΔ bw (calculated as
% of birth weight and expressed as mean ± SD) were determined and
correlated with gestational age (GA) and BW. Data were analyzed via Pearson's
correlation co-efficient and the ordinary least square regression tests. Results: The mean ± standard deviation of GA and BW in 102 enrolled ELBW
infants were 26.1 ± 2 weeks and 779.9 ± 157 g respectively. MWL in the
entire cohort was 14.2 ± 5.4%. After initial loss the BW was regained on
14.5 ± 4.2 postnatal days of life. MWL varied widely within unit GA groups
and was highest in infants born at 23 weeks. MWL correlated inversely with GA
(r= − 0.3, p=0.007) but not with BW (r=0.17, p=0.09). DΔ
bw varied widely and was highest on postnatal day 4. DΔ bw
correlated negatively and significantly with GA during days 1–8 of life (p 0.05
to < 0.01) except for day 2 (p= 0.06). The slopes of regression
coefficients for the two variables were also negative and highly significant
during postnatal days 1–8 (p < 0.01) except for day 2 (p= 0.06).
DΔ bw did not correlate with GA during 9–15 postnatal days and
displayed a positive slope on day 15. Conclusions: MWL is related
inversely to GA and has no relationship with BW in ELBW infant. DΔ
bw is predictable by GA during the first but not the second postnatal week.
The BW is regained on an average of 14 days of postnatal life.
Keywords: Extremely low birth weight infants, postnatal body weight changes, maximum weight loss, daily weight changes, gestational age, birth weight
